Circuit-interrupting device.



C. LE G. FORTESCUE.

CIRCUIT INTERRUPTING DEVICE.

' APPLICATION FILED Auenh 1913. RENEWED DEC. 16.1915.

1 ,184,846 Patented May 30, 1916.

j Z f UNITED STATES PATENT omen.

CHARLES LE G. FORTESCUE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0- WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN SYLVANIA.

CIRCUIT-INTERRUPTING- DEVICE.

Specification of Letters Patent. Pat t d M 30 1916 Application filed August 11, 1913, Serial No; 784,088. Renewed December 16, 1915. Serial No. 67,299.

To all whom it may concern: I

Be it known that I, CHARLES Ln G. Fon- TESCUE, a subject of the King of Great Britain, anda resident of Pittsburgh, in the county of Allegheny and State of Pennsyl- Vania, have invented a new and useful Impredetermined conditions.

The object of my invention is to provide an automatic circuit interrupter which will operate, in anticipation of current disturbances on the circuit with which it is associated, to interrupt the circuit before the current has suflicient time to attain a dangerous or destructive value.

Circuit breakers of the usual type operate directly in accordance with an excess of current. When a momentary overload occurs the tripping magnet is energized and tends.

to trip the breaker but the action'is relatively slow, thus allowing a destructive current to flow and perhaps do a great amount of damage before the circuit is broken. My inven tion relies upon the'change infvoltage across an. inductor to actuate an auxiliary circuit containing. a trip coil. My invention really anticipates a destructive current ,and, when used in conjunction with a high speed breaker, provides an efi'ective and reliable protective device.

Figure 1 of the accompanying drawings is a diagrammatic view of a circuit interrupter'embodying my invention. Fig. 2 is a diagrammatic view of a circuit interrupter embodying a modified form of my invention.

' Fig. 3 .is a diagrammatic view of a circuit cuit with the conductor 2 is a knife switch interrupter embodying another modification and Fig. 4 is a diagrammatic view of ac1rcuit interrupter embodying still another ,modifi'cation.

Referring to the drawings, my invention is incorporated in an electrical circuit 1, receiving current through its conductors 2 and 3 from a-direct current generator 4. In cir- 5 and in circuit with the conductor 3 is a circuit interrupter 6 and an inductor 7. The

1 circuit breaker 6 comprises contact members 8, ,ancperating spring 9, a latch 10 and coil 12.

Referring particularly to Fig. 1', the coil 12 is connected in series with a condenser 13 forming an auxiliary circuit 14 which is placed in parallel with the inductor 7. Referring particularly to Fig. 2, the circuit 14 is connected in arallel with only a part ofthe inductor 7. ieferring to Fig. 3, the coil 12 is connected in series with a spark gap 15 forming an auxiliary circuit 16 which is connected in parallel with the inductor 7. With reference to Fig. 4, the coil 12 is con.- nected to a secondary winding 17- of a transformer 18, the primary winding 19 of which is in series with a resistor 20 forming a circuit 21 which is connected in parallel with theinductor 7.

When a disturbance occurs in the circuit and a momentary rush of current is set up which usually rises to a destructive value, it'is necessary to' have a device which will interrupt the circuit and thus protect it. The normal. direct current will not have any effect on the trip coil 12 because there is either a condenser 13 or a spark gap 15 in series with it, as shown in Figs. 1, 2 and 3, which prevents any flow of direct current of normal voltage. The condenser circuit has a definite potential across it depending upon a tripping magnet 11, provided with a the drop across the reactor 7. When there is a momentary rush of, current, however, the drop across the reactor 7 changes and since the charging current of a condenser depends upon'the voltage across the condenser and the rate of change of this voltage, there will be a fiow of current through'the condenser 9 to open the circuit by separating the con-.

tact members 8.

The operation of the arrangement shown in Fig. 3 is similar-to that of Figs. 1 and 2' in that the current is choked or retarded by the inductor 7 and the voltage rises across its terminals, causing the spark gap 15 to break down which permits the current to flow through the coil 12 to release the latch 10 and, as hereinbefore explained, to operate the spring9 to interrupt the circuit.

The arrangement, as shown in Fig. 4, is

similar in its operation in that the momentaryrush of current is impeded in its course through the inductor 7 and hence the coil 19 and the resistor 20 otter a lower ohmic resistance to the flow of current which will take the path of least resistance. The rapid change of currentin the coil 19 of the transformer 18 will induce a current in the sec-.

'ondary winding 17 of the transformer, a1-

lowing enough current to flow in the coil 12 to open the circuit, as hereinbefore described. My invention may be applied, by those skilled in the art, to any type of circuit breaker without departing from my invention as set forth in the appendedclaims.

I claim as my invention:

1. An interrupter for electric circuits comprising relatively movable contact members, a reactor connected in series relation to the circuit'and means connected in circuit with the reactor and dependent upon a predetermined rate of electrical change in the circuit to cause the disengagement of the contact members. i

2. An interrupter for an electrical clrcult comprising a reactor connected 1n series relation to the circuit, relatively movable conv 4.. An interrupter for electric circuits comprising relatively movable contact members, a reactor connected in series relation to the circuit, and an auxiliarycircuit in shunt relation to the said'reactor comprising a condenser and a tripcoil, said auxiliary circuit being so proportioned that current traverses the .same when the voltage across the said reactor changes-rapidly.

5. An interrupter for a direct-current circuit comprising relatively. movable contact members, a reactor connected in seriesrelation to the circuit, and an auxiliary circuit comprising a trip coil, said auxiliary circuit being so proportioned'that current traverses thesame only when the voltage across the reactor changes'rapidly. Y

6. An interrupter for a direct-current circuit comprising a reactor'connected in series with the cr'rcuit'and a trip coil circuit connected in shunt relation to the reactor and so proportioned that current traverses the same only when the'voltage across the reactor changes rapidly.

7. In an interrupting device for an electric circuit, the combination with areactor interrupting the distributin said circuit.

connected in series relation to the circuit, of an auxiliary circuit having a voltage impressed across its terminals substantially proportional to the potential drop across the said reactor and comprising a condenser and a trip coil, the said auxiliary circuit being so proportioned that current will traverse the same only when the current in a reactor connected in series with the cir-- cuit and a condenser connected across the terminals of the said reactor and in series with the said trip coil.

10. An interrupter for electric circuits comprising a reactor connected in .series with the circuit, a condenser connected across the terminals of the said reactor and means dependent upon a" predetermined rate of condenser discharge for actuating the interrupter to open thecircuit. v

11.1A systemof distribution comprising asource of energy, a reactor connected-in series with the circuit, a condenser connected across the terminalsof the said reactorand means connected in the condenser clrcuit and dependent upon a predetermined electrical change in the condenser circuit for circuit. 12. A system of distribution comprising a source of energy, a distributing circuit, an induction device in the said circuit, a circuit interrupter,means forholding the circuit interrupter closed, and a condenserand .atrip coil connected in shunt circuit. relation to the inductance device for releasing the circuit interrupter in anticipation of a a predetermined electrical change in thedistributing circuit.

13. An terrupter for electric circuit comprising relatively movable contact members, an inductan'cedevice included in the circuit, and a condenser and a trip coil connected in series, said condenser and trip coil bein connected in shunt-circuit relation to the inductance device for separating the contact members anticipation of a'predetermined rate of electrical-change in the 14. In an interrupting device for'an electric circuit, the combination with'a reactor connected in series relation to the of a circuit in shunt relation ,to the sai reactor comprising a spark gap and means for tripping the interrupting device when the voltage across the terminals of the reactor reaches a predetermined value.

15. In an interrupting device for an elec- 5 tric circuit, the combination with a reactor connected in series relation to the circuit, of a circuit in shunt relation to the said reactor comprisin a condenser and means for tripping the interrupting device when the voltage across the terminals of the 10 reactor reaches a predetermined value.

In testimony whereof, I have hereunto subscribed my name this 1st day of August, 1913.

CHARLES LE G. FORTESCUE.

\Vitnesses:

B. B. HINES, L. E. CUNNINGHAM. 

